Cover with locking device

ABSTRACT

A cover, especially for an oil tank, has a locking device with flexible arm carrying locking elements flexibly slidable against a bayonet curved track ridge of a tank opening or tank neck for closure of the tank. The locking device cover is capable of being rotated to close the tank opening without manual downward pressure. A bayonet curved track ridge has spring pressure of the flexible arms eliminating need for manual pressure. The construction is a single integral member made from a plate of spring steel, or made from plastic, of suitable flexibility. It has a bed plate with prongs formed from the edges of an aperture through the bed plate for gripping a pin carried by the cover to secure the locking device to the cover. The flexible arms extend in curved contour from the bed plate and have outer free ends on which the locking elements are located which slidably engage the bayonet track ridge in the tank opening or neck for limited rotation up to a stop for locking the cover to a tank.

The invention comprises a locking device for a tank opening cover,especially for an oil tank, in which the locking device elements worktogether with a bayonet curved track ridge in the tank opening, e.g.,the neck, and wherein the invention can be secured in the tank underspring prestress in coaction with the bayonet track.

BACKGROUND OF THE INVENTION

Covers of this kind which give a quick closure by means of a bayonetjoint, are known for numerous applications, for example, for oil tanks,the cooling water containers of a motor vehicle and the like. Coverlocking devices are carried inside the cover designed for specifictanks. By a slight rotation of the cover, usually assisted by a suitabledownward pressure, the locking elements of such devices are guided by acurved bayonet track ridge internally of the tank neck and generallystopped from rotation after a quarter turn.

A spring tension arrangement provides for a prestressing of the lockingelements and a reliable guiding and a clamping of the cover to the tank.A sealing, with a ventilating drilled hole, if applicable, can beobtained by means of an additional seal.

Known covers consist of several parts, specifically, the actual cover,the inner part with the locking elements and a spring means, generally aspiral spring, for producing the desired prestress. Furthermore, thecover usually also has a member to be inserted as an outer support forthe spiral spring.

Since the sheet metal part in the known constructions constitutes arigid element with the locking elements, the spring had the task ofbringing about a tolerance adjustment along with the prestressing andsealing of the cover.

SUMMARY OF THE INVENTION

The object of the present invention is to produce a cover of the typementioned above that is simple and inexpensive to manufacture, viz., onethat is especially suitable for mass production and closes securely.

That object is accomplished in the invention by using a bed plate havingfastening members to fasten it to the cover, and having flexible armswherein outer free ends have locking elements extending outwardly of thebed plate.

As a result of this arrangement, the cover is simpler and hence cheaperto manufacture because of its novel locking device. Practicallyspeaking, the invention consists only of a single element, specifically,a bed plate from which fastening members to the cover and flexiblelocking elements are integrally formed together with flexible arms. Thissingle integral unit replaces prior art constructions. A spring actionand also a tolerance adjustment during the closing of the cover, thatis, during the guiding of the locking elements of the curved bayonettrack ridge of the cover are obtained by the arms projecting from thebed plate, which act like a centering support in the collar. A simpleembodiment of the invention can consist of having curved flexible armsand projecting freely flexibly from the bed plate.

In the invention, two flexible arms are located opposite each otherdiametrically.

The shape of the curve of the arms and their free ends is made to fitthe inner wall or neck of the tank, so that the locking elements can beguided suitably on the bayonet curved track ridges.

Although fastening of a lock device to a cover itself can beaccomplished in any desired way,

the invention utilizes a simple but very effective fastening of thelocking device to the cover wherein the bed plate has a center apertureinto which a projection such as a tongue or pin carried by the coverenters the aperture to be clamped to the bed plate. The edges of theapertures have upstanding lugs or prongs that fit tightly around thecover pin. Such prongs can fit in recesses of the pin or into undercuts.

Prongs can be bent out of the plane of the bed plate at a slight slantso that the top edges grip against the circumferential wall of the coverpin, a simple unitary assembly and, above all, a unit that is capable ofbeing assembled quickly.

To obtain a precisely defined position for the start of the coverrotation, the cover is keyed to the pin. Thus, the cover pin has aquadrilateral cross section and the bed plate has a matching shapedquadrilateral aperture.

Of course, any cross section of the pin and a matching contour of theaperture shaped to prevent relative rotation is usable.

The locking device can be manufactured simply and cheaply if the bedplate, with the fastening members, the arms and the locking elements,are all punched and shaped from a plate of spring steel.

The locking device can thus be made practically in one procedure inwhich it is only necessary to form parts not in the plane of the bedplate by bending, such as the locking elements.

Instead of spring steel, a plastic can likewise can be substitutedwithin the scope of the invention, and when that is done it is onlynecessary for the plastic to have suitably flexible or elasticcharacteristics, viz, suitable for single integral piece manufacture aswill be understood by persons skilled in the art.

The locking elements, together with the arms, work practically like aplate spring that is fixed at one end, and the elements that projectfrom the bed plate and carry lock means are designed for stability andbalancing of the forces which they exert.

A detailed description of the invention now follows in conjunction withthe appended drawing in which:

FIG. 1 shows a plan view of the locking device of the invention;

FIG. 2 is an elevation partially in section of the locking device ofFIG. 1.

FIG. 3 shows a section longitudinally of the locking device in place onthe neck of a tank.

A cover 1 with a hasp rim 2 has a central pin 3 in its central area thathas a quadrilateral shape in cross section and is slightly conical atleast in the area of its free end. The cover is provided with a gasket 4for sealing that is pressed onto the neck of a tank 5. The tank 5 (FIG.3) has a bayonet curved ridge extending into it with the lower surfaceinclined, as known in the art, the inclined ends briefly flat at thedownmost end 7 with a stop that limits rotational travel of the cover.This provides a positive degree of rotation up to the stop.

As seen in FIGS. 1 and 2 the invention comprises a bed plate 8 to becarried inside the cover, with a central aperture 9 inner area. Twocurved flexible arms 10 and 11 are located diametrically opposite eachother integral with the bed plate.

They carry at their free ends bent formations 12 and 13 which are thelocking members and comprise the locking elements 14 each havingperpendicularly integral parallel stiffening flanges from the lockingmembers 12 and 13 as shown.

The locking elements are suitably shaped to slide resiliently againstthe bayonet track ridge 6 in the cover.

From the edges of the aperture 9, four flexible prongs 15 are outwardlyformed at an inward slant spaced uniformly around the aperture, toflexibly grip tapered pin 3, as illustrated in FIG. 3.

As will be understood, the invention is integrally formed from a plateof spring steel as by a punching process. Thus, prongs 15 and thelocking elements 14 are bent as shown out of the flat plate surface fromwhich the opening 9 and slots 16 for separating the arms 10 and 11 fromthe bed plate are punched out.

The locking device after being formed can be assembled easily with thecover 1. For that purpose, it is only necessary to push the bed plate 8so that aperture 9 fits snugly around the pin 3.

If the bed plate consists of a material harder than the pin 3, which mayconstitute preferably a single piece with the cover 1, the prongs 15have sufficient flexibility whereby the slanted sides have flexing thatcan grip the cover pin 3 for clamping to it. Thus, a reliable joint isguaranteed.

In order to prevent rotational slippage between the pin 3 and bed plate8 a keying can be used. For example, by squaring the cross section ofthe pin to fit onto a similarily squared aperture 9, as shown, or usingany matching piece that has a keying effect.

To close a tank, the cover 1 is placed on the neck of the tank 5, withthe locking elements 14 being inserted in the bayonet curved track ridge6 of the neck. When the cover 1 is twisted slightly, the locking takesplace. No manual pressure is needed and no special spring is requiredbecause of the material of which the invention is made and theflexibility of the two arms 10 and 11 and their construction like platesprings. A ventilating slot 17 can be provided in the cover 1 as shownto ventilate the tank.

We claim:
 1. A cover (1) and locking device for a tank (5) opening, saidlocking device comprising a bed plate (8) having an aperture (9) forreceiving a cover pin (3) carried by the cover for securement of thelocking device to the cover; said bed plate carrying diametricallyopposed locking elements (14) for coaction with a bayonet track ridgeinside the tank;the improvement wherein: said bed plate has flexiblecurved arms (10, 11) carrying said locking elements (14) and saidflexible arms extending from said bed plate (8); said bed plate havingsaid aperture (9) and flexible prongs (15) extending outward from theedge of said aperture for gripping said cover pin to secure said lockingdevice to said cover, wherein said bed plate, flexible arms, andflexible prongs are formed integrally of a spring material.
 2. A coverand locking device as set forth in claim 1, said prongs having anarrangement wherein said aperture has a contour to lock said bed platenon-rotatably to said cover with said cover pin protruding through saidaperture in said bed plate.
 3. A cover and locking device as set forthin claim 2, wherein said cover pin is tapered towards its outer end. 4.A cover and locking device as set forth in claim 1, wherein said baseplate, flexible arms, flexible prongs, and locking elements areintegrally formed of an elastic synthetic material.
 5. A cover as setforth in claim 1, wherein said bed plate, flexible arms, flexibleprongs, and locking elements are formed integrally of spring steel.
 6. Acover and locking device as set forth in claim 1, wherein said lockingelements have flanges extending perpendicularly from the plant of saidflexible arms.
 7. A locking device for the cover of a tank opening madeintegrally from a plate of spring steel comprising:a bed plate (8)having flexible arms (10, 11) extending therefrom, said arms carryinglocking elements (14) capable to coact with a bayonet track ridge of atank; wherein said bed plate has a centrally located aperture (9),fastening prongs (15) extending outwardly from edges of said aperturefor fastening said locking device to a cover pin which forms an integralpart of a cover.
 8. Inner part for a cover, especially for an oil tank,said inner part having locking elements capable to work together with abayonet curved track of a tank to be closed, said inner partcomprising:a bed plate (8) with fastening members (15) forming part ofthe bed plate, for fastening to the cover, curved flexible arms (10, 11)extending from said bed plate and locking elements (14) at the end ofthe flexible arms.
 9. Inner part for a cover as set forth in claim 8,wherein the locking members take the form of bent formations (12, 13)acting as stiffening flanges.